U.S. patent number 9,625,672 [Application Number 14/157,036] was granted by the patent office on 2017-04-18 for imaging apparatus.
This patent grant is currently assigned to Sony Corporation. The grantee listed for this patent is Sony Corporation. Invention is credited to Yoshiteru Kamatani, Kazuhiko Suzuki.
United States Patent |
9,625,672 |
Kamatani , et al. |
April 18, 2017 |
**Please see images for:
( Certificate of Correction ) ** |
Imaging apparatus
Abstract
An imaging apparatus includes a first member including a holding
member, the retaining member holding a lens; a second member
surrounding the first member; an imaging device arranged opposite
to the first member and the lens; and a driving member arranged in
a region adjacent to the first member driving the first member in
the vertical direction relative to the imaging device. The first
member includes at least a first portion and a second portion, the
first portion having a first outer diameter and the second portion
having a second outer diameter smaller than the first outer
diameter, the first and second portions respectively having a first
corner and a second corner, the first and second corners
respectively having a first cutout portion and a second cutout
portion. At least a portion of the driving member is disposed at a
region corresponding to the second portion.
Inventors: |
Kamatani; Yoshiteru (Kanagawa,
JP), Suzuki; Kazuhiko (Kanagawa, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Sony Corporation |
Tokyo |
N/A |
JP |
|
|
Assignee: |
Sony Corporation (Tokyo,
JP)
|
Family
ID: |
43427542 |
Appl.
No.: |
14/157,036 |
Filed: |
January 16, 2014 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20140132826 A1 |
May 15, 2014 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
12814973 |
Jun 14, 2010 |
|
|
|
|
Foreign Application Priority Data
|
|
|
|
|
Jul 10, 2009 [JP] |
|
|
2009-163284 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B
7/10 (20130101); G03B 13/34 (20130101); H04N
5/2254 (20130101); G02B 7/04 (20130101); G02B
13/001 (20130101); H04N 5/2252 (20130101); G02B
7/026 (20130101); G02B 7/09 (20130101); G02B
7/021 (20130101) |
Current International
Class: |
G03B
17/00 (20060101); G02B 7/04 (20060101); G02B
7/09 (20060101); G02B 7/02 (20060101); G02B
13/00 (20060101); G03B 13/34 (20060101); H04N
5/225 (20060101) |
Field of
Search: |
;396/533 ;348/374
;359/823 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
2005-195912 |
|
Jul 2005 |
|
JP |
|
2007-017791 |
|
Jan 2007 |
|
JP |
|
2007-058076 |
|
Mar 2007 |
|
JP |
|
2007-140417 |
|
Jun 2007 |
|
JP |
|
2007-279218 |
|
Oct 2007 |
|
JP |
|
2007-316441 |
|
Dec 2007 |
|
JP |
|
2008-048595 |
|
Feb 2008 |
|
JP |
|
2008-096705 |
|
Apr 2008 |
|
JP |
|
2008-197313 |
|
Aug 2008 |
|
JP |
|
2008-299286 |
|
Dec 2008 |
|
JP |
|
2009-128708 |
|
Jun 2009 |
|
JP |
|
5009-128708 |
|
Jun 2009 |
|
JP |
|
2011-017946 |
|
Jan 2011 |
|
JP |
|
Other References
Japanese Office Action issued Dec. 10, 2014 for corresponding
Japanese Application No. 2009-163284. cited by applicant .
Japanese Office Action issued Dec. 25, 2014 for corresponding
Japanese Application No. 2014-023496. cited by applicant .
Japanese Office Action issued Jun. 30, 2015 for corresponding
Japanese Application No. 2014-023496. cited by applicant .
Korean Office Action Issued Dec. 14, 2015 for Corresponding Korean
Application No. 10-2010-0064000. cited by applicant .
Japanese Office Action Issued Feb. 4, 2016 for Corresponding
Japanese Application No. 2014-023496. cited by applicant .
Korean Office Action issued Jun. 27, 2016 in corresponding Korean
Application No. 10-2010-0064000. cited by applicant .
Korean Office Action issued Aug. 23, 2016 for corresponding Korean
Application No. 10-2010-0064000. cited by applicant .
Korean Office Action issued Dec. 19, 2016 for corresponding Korean
Application No. 10-2016-0121558. cited by applicant.
|
Primary Examiner: Laballe; Clayton E
Assistant Examiner: Chang; Fang-Chi
Attorney, Agent or Firm: Michael Best & Friedrich
LLP
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a Continuation of application Ser. No.
12/814,973, filed on Jun. 14, 2010, and claims priority to Japanese
Patent Application JP 2009-163284 filed in the Japanese Patent
Office on Jul. 10, 2009, the entire contents of which is hereby
incorporated by reference.
Claims
What is claimed:
1. An imaging apparatus comprising: a first member including a
holding member, the holding member configured to hold a lens; a
second member configured to surround the first member; an imaging
device arranged opposite to the first member and the lens; a
driving member arranged in a region adjacent to the first member
and configured to drive the first member in the vertical direction
relative to the imaging device; and a housing configured to
surround the first member, the second member, the driving member,
and the imaging device, wherein the first member includes at least
a first portion and a second portion, the first portion having a
first outer diameter and the second portion having a second outer
diameter smaller than the first outer diameter, the first and
second portions respectively having a first corner and a second
corner, the first and second corners respectively having a first
cutout portion and a second cutout portion, at least a portion of
the driving member is disposed at a region corresponding to the
second portion, and an inner surface of the housing contacts an
outer surface of the imaging device at a first point and an outer
surface of the driving member at a second point, where an inner
dimension of the housing is the same at the first point as at the
second point.
2. The imaging apparatus according to claim 1, wherein the first
cutout portion includes a chamfered edge.
3. The imaging apparatus according to claim 1, wherein the second
cutout portion includes a notched edge.
4. The imaging apparatus according to claim 1, wherein the second
member is configured to surround the second portion, and the second
member is longer than the second portion in the vertical
direction.
5. The imaging apparatus according to claim 1, wherein the entire
driving member is disposed at a region corresponding to the second
portion.
6. The imaging apparatus according to claim 1, wherein the inner
surface of the first member includes a plurality of holding members
respectively configured to hold a plurality of lenses.
7. The imaging apparatus according to claim 6, further comprising:
a first lens disposed in the first portion of the first member; and
a second lens disposed in the second portion of the first member,
wherein a diameter of the first lens is larger than a diameter of
the second lens.
8. The imaging apparatus according to claim 7, wherein the first
lens is located closer to the imaging device than the second
lens.
9. The imaging apparatus according to claim 7, further comprising:
a third lens disposed between the first lens and the second lens,
wherein a diameter of the third lens is larger than the diameter of
the second lens and smaller than the diameter of the first
lens.
10. The imaging apparatus according to claim 1, wherein the driving
member is a voice coil motor including a coil, a magnet, and a
yoke.
11. The imaging apparatus according to claim 1, wherein the driving
member includes a piezoelectric device, a shaft connected to the
piezoelectric device, and a hook connected to the second member and
through which the shaft passes.
12. The imaging apparatus according to claim 1, wherein the driving
member includes a wire made of a shape memory alloy, a hook to
which the wire is hooked, and electrodes connected to the wire.
13. The imaging apparatus according to claim 1, wherein an outer
surface of the second portion includes a first thread; an inner
surface of the second member includes a second thread; and the
first thread and the second thread are engaged to one another.
14. The imaging apparatus according to claim 1, wherein an inner
diameter of the second member is smaller than the first outer
diameter of the first member.
15. A camera comprising the imaging apparatus according to claim
1.
16. The imaging apparatus according to claim 1, wherein an outer
diameter of the second member is smaller than the first outer
diameter of the first member.
17. The imaging apparatus according to claim 1, wherein an inner
diameter of the driving member is smaller than the first outer
diameter of the first member.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an imaging apparatus, and
particularly to an imaging apparatus that allows reduction in size
of a lens driving portion.
2. Description of the Related Art
FIG. 1 shows the configuration of an exemplary imaging apparatus of
related art. An imaging apparatus 10 shown in FIG. 1 includes a
housing 11, a lens barrel 12, and an imaging device 13. The imaging
apparatus 10 is manufactured by assembling the lens barrel 12 and
the imaging device 13 into the housing 11.
Lenses 21, 22, and 23 are assembled into the lens barrel 12 and
held therein. A thread 24 is provided on the outer side surface of
the lens barrel 12. The thread 24 engages a thread (not shown)
provided on a lens carrier 31 disposed in the housing 11. The
thread engagement between the lens barrel 12 and the lens carrier
31 allows the distance to the imaging device 13 to be adjusted at
the time of manufacture (the focus of the lenses to be adjusted).
After the focus adjustment, the lens barrel 12 is glued to the lens
carrier 31 so that the lens barrel 12 is fixed to the lens carrier
31.
Coils 32-1 and 32-2 are provided on the side surface of the lens
carrier 31. The coils 32-1 and 32-2 are shown as separate members
for illustration purposes only, but a single coil 32 is in practice
provided on the side surface of the lens carrier 31. A magnet 33-1
is provided in the housing 11 and faces the coil 32-1. Similarly, a
magnet 33-2 is provided in the housing 11 and faces the coil 32-2.
Each of the magnets 33-1 and 33-2 is provided with a yoke, which is
omitted in FIG. 1. The coil 32, the magnets 33, and the yokes form
a voice coil motor.
When a current is conducted through the coil 32, a force is
produced in the upward or downward direction in FIG. 1. The
produced force moves the lens carrier 31 in the upward or downward
direction. When the lens carrier 31 is moved, the lens barrel 12
fixed to the lens carrier 31 is also moved. The distance between
the lenses 21 to 23 held in the lens barrel 12 and the imaging
device 13 therefore changes. The mechanism described above enables
autofocusing (AF) (see JPA-2007-17791, for example).
SUMMARY OF THE INVENTION
It is desirable in recent years to reduce the size of an AF driver
as the size of digital cameras has been reduced and mobile phones
having a digital camera capability have become popular. The size of
an AF driver can be reduced by reducing the size of an optical
system, such as lenses, but in return the amount of light likely
decreases, disadvantageously resulting in degradation in image
quality. It is therefore not preferable to reduce the size of
lenses or similar optical components in order to reduce the size of
an AF driver. Nevertheless, further reduction in size of the driver
(an imaging apparatus including the driver) is desired, as
described above.
It is difficult to achieve further size reduction unless a change
is made to the configuration shown in FIG. 1. The size of the
imaging apparatus can be reduced by reducing the sizes of the
lenses 21 to 23 to reduce the size of the lens barrel 12 with no
change made to the configuration shown in FIG. 1. In this case,
however, it is difficult to avoid the degradation in image quality
described above.
JP-A-2007-17791 describes an imaging apparatus that has a sector
disposed between a subject and a lens and blocking light incident
to the lens and how to reduce the size of the imaging apparatus.
The imaging apparatus described in JP-A-2007-17791 includes a lens
group containing a plurality of lenses having different diameters,
and the sector is disposed between a subject and the lens group and
blocks light incident to the lens group. The lens group is
accommodated in a lens barrel. The outer circumferential sidewall
of the lens barrel has a plurality of stepped sections having
different diameters corresponding to the diameters of the lenses
accommodated in the lens barrel, and a sidewall recess is formed
along one of the stepped sections. Sector drive means for driving
the sector is disposed in the sidewall recess.
The imaging apparatus described in JP-A-2007-17791 is desired to be
further reduced in size. The imaging apparatus described in
JP-A-2007-17791 has a disadvantageous structure in which, for
example, the lens barrel has no thread mechanism, which does not
allow focus adjustment between the lens group and the imaging
device at the time of manufacture.
Lens driving methods have also been proposed without using the
driving method described with reference to FIG. 1. For example, a
driving method using a piezoelectric device and a driving method
using a shape memory alloy have been proposed. It is desirable that
the other driving methods described above can also be used and the
size of a drive-related portion can be reduced.
Thus, it is desirable to reduce a lens driving portion.
An imaging apparatus according to an embodiment of the invention
includes a first member that holds a lens, a second member to which
the first member is fixed, and drive means for driving the second
member in the vertical direction relative to an imaging plane of an
imaging device. The first member has diameters different from each
other, and a portion having a small diameter has a portion that
engages the second member. The drive means is disposed in a space
created by the difference between the different diameters.
The first member may hold a plurality of lenses having diameters
different from one another and may be shaped to have diameters
corresponding to the diameters of the lenses.
The drive means may be a voice coil motor formed of a coil, a
magnet, and a yoke. The voice coil motor may be disposed in the
space described above. The coil of the voice coil motor may be
disposed on the side surface of the second member.
The drive means may include a piezoelectric device, a shaft
connected to the piezoelectric device, and a hook which is
connected to the second member and through which the shaft passes.
The piezoelectric device, the shaft, and the hook may be disposed
in the space described above.
The drive means may include a wire made of a shape memory alloy, a
hook to which the wire is hooked, and electrodes connected to the
wire. The wire, the hook, and the electrodes may be disposed in the
space described above.
In an imaging apparatus according to another embodiment of the
invention, a thread is provided on a portion of a member that holds
lenses, specifically, on the portion whose diameter corresponds to
the lens having the smallest diameter, and the thread allows the
portion to engage a member that drives the lenses. Drive means is
provided in the space created by the different diameters.
According to the embodiments of the invention, the size of a lens
driving portion can be reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the configuration of an exemplary imaging apparatus of
related art;
FIG. 2 shows the configuration of an imaging apparatus of an
embodiment to which the invention is applied;
FIG. 3 describes the configuration of the imaging apparatus;
FIG. 4 describes the size of the imaging apparatus;
FIGS. 5A and 5B show the configuration of an exemplary imaging
apparatus of related art for comparison;
FIGS. 6A and 6B show the configuration of the imaging apparatus of
another embodiment to which the invention is applied;
FIGS. 7A and 7B show the configuration of an exemplary imaging
apparatus of related art for comparison; and
FIGS. 8A and 8B show the configuration of the imaging apparatus of
another embodiment to which the invention is applied.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of the invention will be described below with reference
to the drawings.
The invention can be applied to an imaging apparatus. The imaging
apparatus described herein is specifically an apparatus
accommodated in, for example, a digital still camera and a mobile
phone having a digital still camera capability. In such an imaging
apparatus, autofocusing (AF) is performed by driving a lens (for
example, moving a lens relative to an imaging device in such a way
that the lens approaches the imaging device or travels away
therefrom).
An imaging apparatus including a driver for performing autofocusing
has a configuration, for example, shown in FIG. 1. Referring to
FIG. 1 again, the imaging apparatus 10 is formed of the housing 11,
which accommodates the lens carrier 31. The lens carrier 31 is
configured to be movable relative to the housing 11 in the upward
and downward directions in FIG. 1 (approaching the imaging device
13 or traveling away therefrom). The lens barrel 12, which
accommodates the plurality of lenses 21 to 23, is disposed in the
lens carrier 31 and fixed thereto.
The embodiments described below primarily relate to the lens barrel
and the lens carrier of the imaging apparatus described above. An
imaging apparatus using a lens barrel and a lens carrier to which
any of the embodiments described below is applied can be smaller
than an imaging apparatus of related art. When such a smaller
imaging apparatus is accommodated in an apparatus, such as a
digital still camera and a mobile phone, the size of the apparatus
can be reduced. Further, the space for the portion other than the
imaging apparatus can be increased, whereby other functions can be
enhanced.
A description will next be made of an imaging apparatus expected to
show the advantageous effects described above. Methods for
performing autofocusing having been proposed include a method using
a voice coil motor (the method described with reference to FIG. 1),
a method using a piezoelectric device, and a method using a wire
made of a shape memory alloy. In the following description, the
embodiments will be described with reference to the methods
described above. That is, the following description includes a
first embodiment in which a voice coil motor is used to perform
autofocusing, a second embodiment in which a piezoelectric device
is used to perform autofocusing, and a third embodiment in which a
wire made of a shape memory alloy is used to perform
autofocusing.
In the following description, a member that holds a lens is
referred to as a lens barrel, a member to which the lens barrel is
fixed is referred to as a lens carrier, and a portion that drives
the lens carrier is referred to as a driver, as appropriate. The
lens barrel is a cylinder shaped in such a way that an upper
diameter (outer diameter) and a lower diameter (outer diameter) are
designed to match the respective lens diameters and hence different
from each other. A portion (thread) that engages the lens carrier
is provided on one of the upper and lower portions of the lens
barrel, the portion having a smaller diameter. The difference in
diameter creates a space, and drive means is provided in the
created space. The drive means in the first to third embodiment
differ from one another as described above and will be described
below.
First Embodiment
A first embodiment will be described below. FIG. 2 shows an
exemplary configuration of an imaging apparatus 100 in the first
embodiment and is a cross-sectional view of the imaging apparatus
100. The imaging apparatus 100 shown in FIG. 2 includes a housing
101, a lens barrel 102, and an imaging device 103. FIG. 3 is an
exploded view of respective parts of the imaging apparatus 100
shown in FIG. 2.
Referring to FIG. 3, lenses 21, 22, and 23 are assembled into the
lens barrel 102 and held therein. A thread 111 is provided on the
outer side surface of the lens barrel 102.
A lens carrier 121 is provided in the housing 101. A thread 122 is
provided on the inner side (inner diameter) of the lens carrier
121. A coil 123 is provided on the outer (outer shape) side surface
of the lens carrier 121. The coil 123 surrounds the side surface of
the lens carrier 121. Magnets 124-1 and 124-2 are provided in
predetermined positions on the inner side (inner diameter) of the
housing 101 and face the coil 123. The magnets 124-1 and 124-2 are
disposed on opposite sides of the coil 123.
Each of the magnets 124-1 and 124-2 is provided with a yoke, but
shown as a combined magnet and yoke in FIGS. 2 and 3 as magnet
124-1 or magnet 124-2. When it is not necessary to distinguish the
magnets 124-1 and 124-2 from each other, the magnets 124-1 and
124-2 are hereinafter simply referred to as magnets 124.
The thread 111 on the lens barrel 102 engages the thread 122
provided on the lens carrier 121. The engagement between the lens
barrel 102 and the lens carrier 121 allows the distance to the
imaging device 103 to be adjusted at the time of manufacture (the
focus of the lenses to be adjusted). After the focus adjustment,
the lens barrel 102 is glued to the lens carrier 121 so that the
lens barrel 102 is fixed to the lens carrier 121.
After the lens barrel 102 is inserted into the housing 101 and
fixed to the lens carrier 121, the imaging device 103 is inserted
into the housing 101 and fixed thereto. The imaging apparatus 100
having the configuration shown in FIG. 2 is manufactured by
sequentially assembling the lens barrel 102 and the imaging device
103 into the housing 101 as described above.
In the imaging apparatus 100 having the configuration described
above, when a current is conducted through the coil 123 provided on
the lens carrier 121, the interaction between the current and the
magnets 124 produces a force oriented in the upward or downward
direction in FIGS. 2 and 3 depending on the direction in which the
current flows. The produced force moves the lens carrier 121 in the
upward or downward direction. When the lens carrier 121 is moved,
the lens barrel 102 fixed to the lens carrier 121 is also moved.
The distance between the lenses 21 to 23 held in the lens barrel
102 and the imaging device 103 therefore changes. Autofocusing (AF)
is performed by the mechanism described above.
The structure of the lens barrel 102 will further be described.
Referring to FIG. 3, the lens barrel 102 has a stepped shape, a
shape having two stepped sections in the configuration shown in
FIG. 3. A stepped section 151 contains the lens 23, and a stepped
section 152 contains the lenses 21 and 22. As shown in FIG. 3, the
sizes of the lenses 21 to 23 satisfy the following relationship.
lens 21<lens 22<lens 23
The diameter of the stepped section 151 containing the lens 23 is
therefore larger than that of the stepped section 152 containing
the lenses 21 and 22. The diameter of the stepped section 151 is
slightly larger than that of the lens 23. The diameter of the
stepped section 152 is slightly larger than that of the lens 22 but
smaller than that of the lens 23.
The thread 111 is provided on the stepped section 152. The thread
111 provided on the stepped section 152 engages the thread 122
provided on the lens carrier 121. The diameter of the lens carrier
121 is sized in such a way that the thread ill engages the thread
122. The diameter of the lens carrier 121 is therefore sized to be
slightly larger than that of the stepped section 152.
Further, the height of the stepped section 152 is shorter than that
of the lens carrier 121. The height used herein means the length in
the up-down direction in FIG. 3 (the direction toward or away from
the imaging device). The height of the lens carrier 121 is
determined in such a way that the stepped section 151 of the lens
barrel 102 does not come into contact with an end of the lens
carrier 121 when the lens barrel 102 is fixed to the lens carrier
121.
The imaging apparatus 10 of related art is now compared with the
imaging apparatus 100 in the first embodiment. The upper portion of
FIG. 4 shows the configuration of the imaging apparatus 10 of
related art shown in FIG. 1, and the lower portion of FIG. 4 shows
the configuration of the imaging apparatus 100 in the first
embodiment of the invention shown in FIG. 2.
Each of the imaging apparatus 10 and the imaging apparatus 100
includes the lenses 21 to 23. The imaging apparatus 10 and the
imaging apparatus 100 therefore do not differ from each other in
terms of optical system and can hence capture images having the
same image quality. Further, the imaging device 13 in the imaging
apparatus 10 and the imaging device 103 in the imaging apparatus
100 have the same number of pixels and can capture images having
the same image quality in this regard as well.
It is, however, obvious that the imaging apparatus 100 is smaller
than the imaging apparatus 10. The reason for this is that the lens
barrel 102 in the imaging apparatus 100 has a stepped shape and the
diameter of the stepped section 152 accommodating the smaller
lenses is smaller than the diameter of the stepped section 151
accommodating the larger lens. The size of the imaging apparatus
100 can be reduced accordingly. The size of the imaging apparatus
100 is reduced because the space created by the difference between
the stepped sections 151 and 152, specifically, the difference in
diameter between the stepped sections 151 and 152, accommodates the
lens carrier 121, the thread 122, the coil 123, and the magnets
124.
That is, the size of the imaging apparatus 100 can be reduced by
shaping the lens barrel 102 in such a way that the diameter thereof
gradually decreases in correspondence with the sizes of the lenses
to be accommodated, providing the thread 111 on the stepped section
having the smaller diameter so that the threaded portion engages
the lens carrier 121, and assembling a driver including the coil
123 and the magnets 124 on the side where the diameter is
smaller.
In the above description of "shaping the lens barrel 102 in such a
way that the diameter thereof gradually decreases in correspondence
with the sizes of the lenses to be accommodated," "the diameter
thereof gradually decreases" means that the following shapes can be
employed. That is, for example, a stepped shape, like the stepped
sections 151 and 152 shown in FIG. 3, can be employed. Although not
shown, when three lenses, such as the lenses 21 to 23 shown in FIG.
3, are incorporated, a stepped shape not formed of two stepped
sections but formed of three stepped sections corresponding to the
number of lenses can be employed.
Alternatively, although not shown, instead of a stepped shape, for
example, a cone shape (part of a cone shape) whose diameter
gradually and continuously decreases in the direction away from the
imaging device 103 can be employed. Still alternatively, for
example, a combined shape in which the threaded portion
(corresponding to the stepped section 152 in FIG. 3) has a
cylindrical shape and the non-threaded portion (corresponding to
the stepped section 151 in FIG. 3) has part of a cone shape can be
employed. Still alternatively, any shape one can think of from the
shapes described above can be employed.
In the imaging apparatus 10 of related art shown in the upper
portion of FIG. 4, the lens carrier 31 is positioned outside the
lens barrel 12, and the coil 32 and the magnets 33 are further
positioned outside the lens carrier 31. That is, when the
configuration described above is employed, the diameter of the lens
carrier 31 is greater than that of the lens barrel 12, and the coil
32 and the magnets 33 are further positioned outside the
large-diameter lens carrier 31, disadvantageously resulting in an
increased size of the imaging apparatus 10 itself.
On the other hand, since the imaging apparatus 100 shown in the
lower portion of FIG. 4, to which the first embodiment of the
invention is applied, has the configuration described above, the
lens carrier 121 is positioned outside the lens barrel 102 but
inside the largest-diameter portion (outer diameter) of the lens
barrel 102. Further, the coil 123 and the magnets 124 positioned
outside the lens carrier 121 are positioned inside the outer
diameter of the lens barrel 102. Since none or only part of the
lens carrier 121, the coil 123, and the magnets 124 is thus
positioned outside the outer diameter of the lens barrel 102, the
size of the imaging apparatus 100 itself is reduced.
In other words, the diameter of the lens barrel 102 on the side
where the imaging device 103 is present is large, whereas the
diameter of the lens barrel 102 on the opposite side is small.
Since the diameters of the two portions of the lens barrel 102
differ from each other, a space is created where the difference is
present. Accommodating drive means (the coil 123, the magnets 124,
and the yokes in this case) for vertically moving the lens carrier
121 relative to the imaging plane of the imaging device 103 in the
space allows the size of the imaging apparatus 100 to be
reduced.
As described above, the size of the imaging apparatus can be
reduced by applying the invention. Further, the size reduction will
not degrade the quality of a captured image.
The focus adjustment carried out at the time of manufacture by
using the engagement between the lens barrel 102 and the lens
carrier 121 can be carried out in the same manner as the imaging
apparatus 10 of related art.
Second Embodiment
A second embodiment will be described below. The second embodiment
relates to a case where a piezoelectric device is used to perform
autofocusing. A piezoelectric device is a passive device using a
piezoelectric effect in which a force applied to a piezoelectric
member is converted into a voltage and vice versa. To describe an
imaging apparatus using a piezoelectric device to perform
autofocusing, the configuration of an imaging apparatus of related
art is first shown in FIGS. 5A and 5B for comparison. FIG. 5A is a
top view of an imaging apparatus 200, and FIG. 5B is a side view
(cross-sectional view) of the imaging apparatus 200.
The imaging apparatus 200 includes a housing 201, a lens barrel
202, and an imaging device 203. Lenses 21, 22, and 23 are assembled
into the lens barrel 202 and held therein. A thread 211 is provided
on the outer side surface of the lens barrel 202.
A lens carrier 221 is provided in the housing 201. A thread 222 is
provided on the inner side (inner diameter) of the lens carrier
221. A slide hook 223 is provided in a predetermined position on
the outer (outer shape) side surface of the lens carrier 221. One
of the ends of the slide hook 223 is connected to the lens carrier
221, and the other end has a circular shape having a circular hole
at the center thereof. A shaft 224 passes through the hole.
A piezoelectric device 225 fixed to the housing 201 is attached to
the shaft 224. When a current is conducted through the
piezoelectric device 225, a force is produced and then the slide
hook 223 slides. When the slide hook 223 slides, the lens carrier
221 moves relative to the housing 201 in the upward or downward
direction (the direction toward or away from the imaging device
203). Autofocusing is thus performed.
In the imaging apparatus 200 of related art shown in FIGS. 5A and
5B, the lens carrier 221 is positioned outside the lens barrel 202
and the slide hook 223, the shaft 224, and the piezoelectric device
225 are further positioned outside the lens carrier 221. That is,
when the configuration described above is employed, the diameter of
the lens carrier 221 is greater than that of the lens barrel 202,
and the slide hook 223, the shaft 224, and the piezoelectric device
225 are further positioned outside the large-diameter lens carrier
221, resulting in an increased size of the imaging apparatus 200
itself.
To address the problem, the imaging apparatus in the second
embodiment to which the invention is applied has the configuration
shown in FIGS. 6A and 6B to reduce the size of the imaging
apparatus. FIG. 6A is a top view of an imaging apparatus 250, and
FIG. 6B is a side view (cross-sectional view) of the imaging
apparatus 250.
The imaging apparatus 250 shown in FIGS. 6A and 6B has a
configuration that is basically the same as that of the imaging
apparatus 200 of related art shown in FIGS. 5A and 5B. The imaging
apparatus 250 includes a housing 251, a lens barrel 252, and an
imaging device 253. Lenses 21, 22, and 23 are assembled into the
lens barrel 252 and held therein. A thread 261 is provided on the
outer side surface of the lens barrel 252.
A lens carrier 271 is provided in the housing 251. A thread 272 is
provided on the inner side (inner diameter) of the lens carrier
271. A slide hook 273 is provided in a predetermined position on
the outer (outer shape) side surface of the lens carrier 271. One
of the ends of the slide hook 273 is connected to (integrated with)
the lens carrier 271, and the other end has a circular shape having
a circular hole at the center thereof. A shaft 274 passes through
the hole.
A piezoelectric device 275 fixed to the housing 251 is attached to
the shaft 274. When a current is conducted through the
piezoelectric device 275, a force is produced and then the slide
hook 273 slides. When the slide hook 273 slides, the lens carrier
271 moves relative to the housing 251 in the upward or downward
direction (the direction toward or away from the imaging device
253). Autofocusing is thus performed.
The structure of the lens barrel 252 will further be described.
Referring to FIG. 6B, the lens barrel 252 has a stepped shape, a
shape having two stepped sections in the configuration shown in
FIG. 6B. A stepped section 281 contains the lens 23, and a stepped
section 282 contains the lenses 21 and 22. As shown in FIG. 6B, the
sizes of the lenses 21 to 23 satisfy the following relationship.
lens 21<lens 22<lens 23
The diameter of the stepped section 281 containing the lens 23 is
therefore larger than that of the stepped section 282 containing
the lenses 21 and 22. The diameter of the stepped section 281 is
slightly larger than that of the lens 23. The diameter of the
stepped section 282 is slightly larger than that of the lens 22 but
smaller than that of the lens 23.
The thread 261 is provided on the stepped section 282. The thread
261 provided on the stepped section 282 engages the thread 272
provided on the lens carrier 271. The diameter of the lens carrier
271 is sized in such a way that the thread 261 engages the thread
272. The diameter of the lens carrier 271 is therefore sized to be
slightly larger than that of the stepped section 282.
Further, the height of the stepped section 282 is shorter than the
height of the lens carrier 271. The height used herein means the
length in the up-down direction in FIG. 6B (the direction toward or
away from the imaging device 253). The height of the lens carrier
271 is determined in such a way that the stepped section 281 of the
lens barrel 252 does not come into contact with an end of the lens
carrier 271 when the lens barrel 252 is fixed to the lens carrier
271.
The imaging apparatus 200 of related art is now compared with the
imaging apparatus 250 in the second embodiment. Each of the imaging
apparatus 200 and the imaging apparatus 250 includes the lenses 21
to 23. The imaging apparatus 200 and the imaging apparatus 250
therefore do not differ from each other in terms of optical system
and can hence capture images having the same image quality.
Further, the imaging device 203 in the imaging apparatus 200 and
the imaging device 253 in the imaging apparatus 250 have the same
number of pixels and can capture images having the same image
quality in this regard as well.
It is, however, obvious that the imaging apparatus 250 is smaller
than the imaging apparatus 200. The reason for this is that the
lens barrel 252 in the imaging apparatus 250 has a stepped shape
and the diameter of the stepped section 282 accommodating the
smaller lenses is smaller the diameter of the stepped section 281
accommodating the larger lens. The size of the imaging apparatus
250 can be reduced accordingly. The size of the imaging apparatus
250 is reduced because the space created by the difference between
the stepped sections 281 and 282, specifically, the difference in
diameter between the stepped sections 281 and 282, accommodates all
or part of the lens carrier 271, the slide hook 273, and the shaft
274.
That is, the size of the imaging apparatus 250 can be reduced by
shaping the lens barrel 252 in such a way that the diameter thereof
gradually decreases in correspondence with the sizes of the lenses
to be accommodated, providing the thread 261 on the stepped section
having the smaller diameter so that the threaded portion engages
the lens carrier 271, and assembling a driver including the slide
hook 273, the shaft 274, and the piezoelectric device 275 on the
side where the diameter is smaller.
In the above description of "shaping the lens barrel 252 in such a
way that the diameter thereof gradually decreases in correspondence
with the sizes of the lenses to be accommodated," "the diameter
thereof gradually decreases" means that the following shapes can be
employed. That is, for example, a stepped shape, like the stepped
sections 281 and 282 shown in FIG. 6B, can be employed. Although
not shown, when three lenses, such as the lenses 21 to 23 shown in
FIG. 6B, are incorporated, a stepped shape not formed of two
stepped sections but formed of three stepped sections corresponding
to the number of lenses can be employed.
Alternatively, although not shown, instead of a stepped shape, for
example, a cone shape (part of a cone shape) whose diameter
gradually and continuously decreases in the direction away from the
imaging device 253 can be employed. Still alternatively, for
example, a combined shape in which the threaded portion
(corresponding to the stepped section 282 in FIG. 6B) has a
cylindrical shape and the non-threaded portion (corresponding to
the stepped section 281 in FIG. 6B) has part of a cone shape can be
employed. Still alternatively, any shape one can think of from the
shapes described above can be employed.
The imaging apparatus 200 of related art shown in FIGS. 5A and 5B
disadvantageously has a structure that causes an increase in size
of the imaging apparatus 200 itself, as described above. However,
since the imaging apparatus 250 shown in FIGS. 6A and 6B, to which
the second embodiment of the invention is applied, has the
configuration described above, the lens carrier 271 is positioned
outside the lens barrel 252 but inside the largest-diameter portion
of the lens barrel 252.
Further, all or part of the driver including the slide hook 273,
the shaft 274, and the piezoelectric device 275 positioned outside
the lens carrier 271 is positioned inside the largest-diameter
portion (largest outer diameter) of the lens barrel 252. Since none
or only part of the lens carrier 271, the slide hook 273, the shaft
274, and the piezoelectric device 275 is thus positioned outside
the largest outer diameter of the lens barrel 252, the size of the
imaging apparatus 250 itself is reduced.
In other words, the diameter of the lens barrel 252 on the side
where the imaging device 253 is present is large, whereas the
diameter of the lens barrel 252 on the opposite side is small.
Since the diameters of the two portions of the lens barrel 252
differ from each other, a space is created where the difference is
present. Accommodating drive means (the slide hook 273, the shaft
274, and the piezoelectric device 275 in this case) for vertically
moving the lens carrier 271 relative to the imaging plane of the
imaging device 253 in the space allows the size of the imaging
apparatus 250 to be reduced.
As described above, the size of the imaging apparatus can be
reduced by applying the invention.
The focus adjustment carried out at the time of manufacture by
using the engagement between the lens barrel 252 and the lens
carrier 271 can be carried out in the same manner as the imaging
apparatus 200 of related art.
The imaging apparatus 250 shown in FIGS. 6A and 6B includes one set
of the slide hook 273 and the shaft 274, two to four sets of a
slide hook and a shaft can be provided. The sets of a slide hook
and a shaft other than the set of the slide hook 273 and the shaft
274 are provided to support the lens carrier 271 but provided with
no piezoelectric device. Providing a plurality of sets of a slide
hook and a shaft in the imaging apparatus 250 does not increase the
size of the configuration of the imaging apparatus 250, but the
imaging apparatus 250 can still be reduced in size.
Third Embodiment
A third embodiment will be described below. The third embodiment
relates to a case where a wire made of a shape memory alloy is used
to perform autofocusing. A shape memory alloy is characterized in
that the length thereof increases or decreases when a current is
conducted therethrough. To describe an imaging apparatus using a
wire made of a shape memory alloy to perform autofocusing, the
configuration of an imaging apparatus of related art is first shown
in FIGS. 7A and 7B for comparison. FIG. 7A is a top view of an
imaging apparatus 300, and FIG. 7B is a side view (cross-sectional
view) of the imaging apparatus 300.
The imaging apparatus 300 includes a housing 301, a lens barrel
302, and an imaging device 303. Lenses 21, 22, and 23 are assembled
into the lens barrel 302 and held therein. A thread 311 is provided
on the outer side surface of the lens barrel 302.
A lens carrier 321 is provided in the housing 301. A thread 322 is
provided on the inner side (inner diameter) of the lens carrier
321. Hooks 323-1 and 323-2 are provided in predetermined positions
on the outer (outer shape) side surface of the lens carrier 321.
The hooks 323-1 and 323-2 are disposed on opposite sides of the
lens carrier 321. A wire 332 made of a shape memory alloy is hooked
to the hooks 323-1 and 323-2 (hereinafter simply referred to as the
hooks 323 when they are not necessary to be distinguished and the
same applies to other portions in the following description).
The wire 332 is also connected to electrodes 331-1 and 331-2. When
a current is conducted from the electrodes 331-1 and 331-2 through
the wire 332 and the temperature thereof increases, the wire 332
made of a shape memory alloy decreases in length. When the length
of the wire 332 decreases, the hooks 323 to which the wire 332 is
hooked are lifted relative to the housing 301.
Since the hooks 323 are integrated with the lens carrier 321, the
hooks 323 lifted relative to the housing 301 lift the lens carrier
321 relative to the housing 301. In this way, the lens carrier 321
is driven. Conversely, when the current flowing through the wire
332 is terminated, the temperature thereof decreases and the length
thereof increases. When the length of the wire 332 increases
(returns back to its original length), the hooks 323 and hence the
lens carrier 321 are lowered.
The lens barrel 302, which holds the lenses, fits into the lens
carrier 321. Driving the lens carrier 321 in the way described
above therefore changes the position of the lenses held in the lens
barrel 302 and hence the focal distance is adjusted. That is,
autofocusing is performed.
In the imaging apparatus 300 of related art shown in FIGS. 7A and
7B, the lens carrier 321 is positioned outside the lens barrel 302,
and the hooks 323, the wire 332, and the electrodes 331 are further
positioned outside the lens carrier 321. That is, when the
configuration described above is employed, the diameter of the lens
carrier 321 is greater than that of the lens barrel 302, and the
hooks 323, the wire 332, and the electrodes 331 are further
positioned outside the large-diameter lens carrier 321, resulting
in an increased size of the imaging apparatus 300 itself.
To address the problem, the imaging apparatus in the third
embodiment to which the invention is applied has the configuration
shown in FIGS. 8A and 8B to achieve size reduction. FIG. 8A is a
top view of an imaging apparatus 350, and FIG. 8B is a side view
(cross-sectional view) of the imaging apparatus 350.
The imaging apparatus 350 shown in FIGS. 8A and 8B has a
configuration that is basically the same as that of the imaging
apparatus 300 of related art shown in FIGS. 7A and 7B. The imaging
apparatus 350 includes a housing 351, a lens barrel 352, and an
imaging device 353. Lenses 21, 22, and 23 are assembled into the
lens barrel 352 and held therein. A thread 361 is provided on the
outer side surface of the lens barrel 352.
A lens carrier 371 is provided in the housing 351. A thread 372 is
provided on the inner side (inner diameter) of the lens carrier
371. Hooks 373-1 and 373-2 are provided in predetermined positions
on the outer (outer shape) side surface of the lens carrier 371.
The hooks 373-1 and 373-2 are disposed on opposite sides of the
lens carrier 371. A wire 382 made of a shape memory alloy is hooked
to the hooks 373-1 and 373-2.
The wire 382 is also connected to electrodes 381-1 and 381-2. When
a current is conducted from the electrodes 381-1 and 381-2 through
the wire 382 and the temperature thereof increases, the wire 382
made of a shape memory alloy decreases in length. When the length
of the wire 382 decreases, the hooks 373 to which the wire 382 is
hooked are lifted relative to the housing 351.
Since the hooks 373 are integrated with the lens carrier 371, the
hooks 373 lifted relative to the housing 351 lift the lens carrier
371 relative to the housing 351. In this way, the lens carrier 371
is driven. Conversely, when the current flowing through the wire
382 is terminated, the temperature thereof decreases and the length
thereof increases. When the length of the wire 382 increases
(returns back to its original length), the hooks 373 and hence the
lens carrier 371 are lowered.
The lens barrel 352, which holds the lenses, fits into the lens
carrier 371. Driving the lens carrier 371 in the way described
above therefore changes the position of the lenses held in the lens
barrel 352 and hence the focal distance is adjusted. That is,
autofocusing is performed.
The structure of the lens barrel 352 will further be described.
Referring to FIG. 8B, the lens barrel 352 has a stepped shape, a
shape having two stepped sections in the configuration shown in
FIG. 8B. A stepped section 391 contains the lens 23, and a stepped
section 392 contains the lenses 21 and 22. As shown in FIG. 8B, the
sizes of the lenses 21 to 23 satisfy the following relationship.
lens 21<lens 22<lens 23
The diameter of the stepped section 391 containing the lens 23 is
therefore larger than that of the stepped section 392 containing
the lenses 21 and 22. The diameter of the stepped section 391 is
slightly larger than that of the lens 23. The diameter of the
stepped section 392 is slightly larger than that of the lens 22 but
smaller than that of the lens 23.
The thread 361 is provided on the stepped section 392. The thread
361 provided on the stepped section 392 engages the thread 372
provided on the lens carrier 371. The diameter of the lens carrier
371 is sized in such a way that the thread 361 engages the thread
372. The diameter of the lens carrier 371 is therefore sized to be
slightly larger than that of the stepped section 392.
Further, the height of the stepped section 392 is shorter than the
height of the lens carrier 371. The height used herein means the
length in the up-down direction in FIG. 8B (the direction toward or
away from the imaging device 353). The height of the lens carrier
371 is determined in such a way that the stepped section 391 of the
lens barrel 352 does not come into contact with an end of the lens
carrier 371 when the lens barrel 352 is fixed to the lens carrier
371.
The length of the hooks 373 attached to the lens carrier 371 is
sized in such a way that part of the tips of the hooks 373 extends
off the largest diameter (largest outer diameter) of the lens
barrel 352 or the tips are preferably within the diameter of the
lens barrel 352.
The imaging apparatus 300 (FIGS. 7A and 7B) of related art is now
compared with the imaging apparatus 350 (FIGS. 8A and 8B) in the
third embodiment. Each of the imaging apparatus 300 and the imaging
apparatus 350 includes the lenses 21 to 23. The imaging apparatus
300 and the imaging apparatus 350 therefore do not differ from each
other in terms of optical system and can hence capture images
having the same image quality. Further, the imaging device 303 in
the imaging apparatus 300 and the imaging device 353 in the imaging
apparatus 350 have the same size or the same number of pixels and
can capture images having the same image quality in this regard as
well.
It is, however, obvious that the imaging apparatus 350 is smaller
than the imaging apparatus 300. The reason for this is that the
lens barrel 352 in the imaging apparatus 350 has a stepped shape
and the diameter of the stepped section 392 accommodating the
smaller lenses is smaller than the diameter of the stepped section
391 accommodating the larger lens. The size of the imaging
apparatus 350 can be reduced accordingly. The size of the imaging
apparatus 350 is reduced because the space created by the
difference between the stepped sections 391 and 392, specifically,
the difference in diameter between the stepped sections 391 and
392, accommodates all or part of the lens carrier 371, the hooks
373, and the electrodes 381.
That is, the size of the imaging apparatus 350 can be reduced by
shaping the lens barrel 352 in such a way that the diameter thereof
gradually decreases in correspondence with the sizes of the lenses
to be accommodated, providing the thread 361 on the stepped section
having the smaller diameter so that the threaded portion engages
the lens carrier 371, and assembling a driver including the hooks
373, the electrodes 381, and the wire 382 on the side where the
diameter is smaller.
In the above description of "shaping the lens barrel 352 in such a
way that the diameter thereof gradually decreases in correspondence
with the sizes of the lenses to be accommodated," "the diameter
thereof gradually decreases" means that the following shapes can be
employed. That is, for example, a stepped shape, like the stepped
sections 391 and 392 shown in FIG. 8B, can be employed. Although
not shown, when three lenses, such as the lenses 21 to 23 shown in
FIG. 8B, are incorporated, a stepped shape not formed of two
stepped sections but formed of three stepped sections corresponding
to the number of lenses can be employed.
Alternatively, although not shown, instead of a stepped shape, for
example, a cone shape (part of a cone shape) whose diameter
gradually and continuously decreases in the direction away from the
imaging device 353 can be employed. Still alternatively, for
example, a combined shape in which the threaded portion
(corresponding to the stepped section 392 in FIG. 8B) has a
cylindrical shape and the non-threaded portion (corresponding to
the stepped section 391 in FIG. 8B) has part of a cone shape can be
employed. Still alternatively, any shape one can think of from the
shapes described above can be employed.
The imaging apparatus 300 of related art shown in FIGS. 7A and 7B
disadvantageously has a structure that causes an increase in size
of the imaging apparatus 300 itself, as described above. However,
since the imaging apparatus 350 shown in FIGS. 8A and 8B, to which
the third embodiment of the invention is applied, has the
configuration described above, the lens carrier 371 is positioned
outside the lens barrel 352 but inside the largest-diameter (outer
diameter) portion of the lens barrel 352.
Further, all or part of the driver including the hooks 373, the
electrodes 381, and the wire 382 positioned outside the lens
carrier 371 is positioned inside the largest-diameter portion of
the lens barrel 352. Since none or only part of the lens carrier
371, the hooks 373, the electrodes 381, and the wire 382 is thus
positioned outside the largest diameter of the lens barrel 352, the
size of the imaging apparatus 350 itself is reduced.
In other words, the diameter of the lens barrel 352 on the side
where the imaging device 353 is present is large, whereas the
diameter of the lens barrel 352 on the opposite side is small.
Since the diameters of the two portions of the lens barrel 352
differ from each other, a space is created where the difference is
present. Accommodating drive means (the hooks 373, the electrodes
381, and the wire 382 in this case) for vertically moving the lens
carrier 371 relative to the imaging plane of the imaging device 353
in the space allows the size of the imaging apparatus 350 to be
reduced.
As described above, the size of the imaging apparatus can be
reduced by applying the invention. Further, the size reduction will
not degrade the quality of a captured image.
The focus adjustment carried out at the time of manufacture by
using the engagement between the lens barrel 352 and the lens
carrier 371 can be carried out in the same manner as the imaging
apparatus 300 of related art.
The imaging apparatus 350 shown in FIGS. 8A and 8B includes the two
hooks 373, the two electrodes 381, and the wire 382 connected to
the hooks 373 and the electrodes 381 and surrounding the lens
carrier 371. The imaging apparatus 350 may alternatively include
one of the hooks 373, the two electrodes 381, and the wire 382
connected to the hook 373 and the electrodes 381 and surrounding
the lens carrier 371. That is, the imaging apparatus 350 can, for
example, be configured in such a way that the ends of the wire 382
are connected to the electrodes 381-1 and 381-2 and the hook 373-1
(or hook 373-2) is positioned in a central portion of the wire
382.
The configuration described above does not increase the size of the
configuration of the imaging apparatus 350, but the imaging
apparatus 350 can still be reduced in size.
The above first to third embodiments have been described with
reference to a case where the lens closer to the imaging device is
larger and the size of the lenses decreases in the direction away
from the imaging device. The invention is, however, not limited to
the lens layout described above. That is, for example, the
invention can be applied to a case where the lens farther away from
the imaging device is larger and the size of the lenses decreases
in the direction toward the imaging device.
When the lens layout described above is employed, the threads and
the driver are provided on the side where the stepped portion
accommodating smaller lenses is present. The size of the imaging
apparatus can, of course, be reduced even when the lens layout
described above is employed, as in the above embodiments.
The above embodiments have been described with reference to the
imaging apparatus including the three lenses 21 to 23, but the
invention is not necessarily applied to an imaging apparatus
including three lenses. That is, the invention can be applied to an
imaging apparatus including a plurality of lenses.
When a plurality of lenses are provided and the diameter of the
lenses increases (or decreases) toward the imaging device, the lens
barrel holding the plurality of lenses is configured not to simply
have a cylindrical shape but have a stepped shape according to the
diameters of the lenses or a shape at least part of which gradually
decreases in diameter. Shaping the lens carrier that holds the lens
barrel in accordance with the shape of the lens barrel provides a
sufficient space between the lens carrier and the inner wall of the
lens module on the side where a subject is present, whereby the
actuator can be disposed in the space. The lens module can
therefore be reduced in size.
In an imaging apparatus of related art having a structure in which
no thread is provided on the lens barrel and the lens carrier, the
focus adjustment with respect to the imaging device may not be
carried out. In the present invention, threads are provided on the
lens barrel and the lens carrier. Providing threads on the lens
barrel and the lens carrier allows the focus adjustment with
respect to the imaging device to be carried out, for example, at
the time of manufacture.
The stroke typically required to perform autofocusing can be
minimized and the requirements on actuator characteristics can be
lowered by applying the invention. Further, the resultant smaller
stroke or movable range advantageously reduces power
consumption.
Embodiments of the invention are not limited to those described
above, but a variety of changes can be made to the extent that they
do not depart from the spirit of the invention.
The present application contains subject matter related to that
disclosed in Japanese Priority Patent Application JP 2009-163284
filed in the Japan Patent Office on Jul. 10, 2009, the entire
contents of which is hereby incorporated by reference.
* * * * *